Chisel



(No Model.)

J. E. DONALDSON.

GHISEL.

Patented Apri- 12, 1887.

75. g E- I aya' UNITED STATES PATENT OFFICE.

JOHN ED DONALDSON, OF MONTEZUMA, INDIANA.

CHISEL.

SPECIFICATION forming part of Letters Patent No. 361,145, dated April 12, 1857. Application filed May 18, 1586. SerialNo. 202,555. (No model.)

To all whom, t may concern:

Be it known that I, JOHN ED DONALDSON, a citizen of the United States, residing at Montezuma, in the'county of Parke and State of In diana, have invented a new and useful Im` provement in Ghisels, of which the following is a specification.

My invention relates to an improved chisel for mortisin'g-machines; and it consists of the peculiar construction and combination of parts, substantially as hereinafter fully set forth, and specically pointed out in the claims.

The object of myinvention is to provide an improved chisel which shall be very simple, strong, and durable in construction, cheap and inexpensive of manufacture, and thoroughly effective in operation.

My improved chisel is made in a single piece of metal and provided with an interior chippassage and with lateral outlets for the escape of the chips, and the inclosing walls or arch 7 of the outlet is of peculiar form to rapidly and effectually expel or discharge the chips.

The device can be used in any class of foot or power machine for cutting mortises in fencerails, balustrades, or the like, and it can be also adapted as a hand implement or tool.

In the accompanying drawings, Figure l is a perspective view of so much of a mortisingmachine as is necessary for a proper understanding of my invention, showing my improved chisel adjusted for use therein. Fig. 2 is an enlarged perspective view of my improved chiseldetached from the machine. Fig. 3 is a vertical central sectional view thereof on the line l 1 of Fig. 2. Figs. 4. and 5 are transverse horizontal sectional views on the lines 2 2 and 3 3, respectively, of Fig. 3. Fig. 6 is a view of the chisel adapted for use as a hand implement or tool.

Referring to the drawings, in which like letters of reference denote corresponding partsv in all the igures, A designates my improved chisel for cutting mortises,which is of the desired size and substantially square in crosssection. q

The chisel is made hollow in form to provide an interior scrap or chip passage, B, and the lower edges of the chisel are beveled or inclined outwardly to form the cutting-edges b, which act upon the work.

The upper end of the chisel is provided willi lateral or side openings, C,which'pro vide the exit or discharge openings for the chips, and the sides d ofthe chisel are tapered or inclined inwardly toward each other to form an arch, D, and they meet together atthe center of the chip-passage B of the device.

The chisel is provided Withan integral stock or shank, D', which is provided with a shoulder, d', and this stock is to be fitted in the mandrel E of a machine for mortising fence-posts, (shown in Fig. 1;) but I would have it understood that I do not confine myself to the use of my invention in the machine shown herein, as it can be used in any class of mortising-machine.

I The exit-openings C for the chips are curved at their lower edges, to provide large passages for the free escape of the chips therethrough fromvthe interior chip-passage, and the upper edges of the said openings are tapered or inclined toward each other. The inner opposing faces of' the arch or sides d of the chisel are provided with inwardly-projecting ribs or iianges e, which are formed integrally therewith and arranged longitudinally and centrally thereon. These ribs are substantially V- shaped in form, and the lower edges of the ribs gradually decrease until they merge into the sides d, while the upper edges meet or join together, and by this peculiar construction and arrangement of the ribs and the lateral discharge-exits in the chisel the chips, as they are forced or elevated up the interior scrap passage, are effectively and rapidly discharged and broken.

The exterior diameter of the squared cham- Ybered en-d of the chisel corresponds or is equal to the diameter of the mortise to be cut, and

the peculiar bevel of the cutting-edges b facilil tates the elevation of the chips inthe interior chip-passage, vwhile the lateral openings and the projecting interior ribs discharge the chips from the chisel. The stock or shank may be extended or lengthened a sufficient distance and provided with an enlarged head, f, to adapt the chisel for use as a hand tool or implement, as shown in Fig. 6, the head f receiving the blows of a hammer or mallet.

When a mortise is to be cut by my improved chisel, a hole of very nearly the diameter of the mortise desired is first bored into IOO and through the Work by a machine or implement of suitable character, and the chisel is then brought down upon and forced through the work to cut the mortise, the chips passing through the interior passage and striking the inwardly-proj ccting ribs, by which they are deiiected laterally through'the escape-openings.

By using a chisel constructed in accordance with my invention in a mortising-machine of either hand or foot, the mortises can be rapidly and accurately cut, and the chips are dis charged Without stopping the machine or requiring the operator to clear the chips from the chisel.

The chisel can be made by a mechanic or blacksmith of ordinary skill, and it is simple and durable in construction, cheap and inexpensive ofmanu facture, and thoroughly effective for the purposes designed.

Having thus fully described my invention, whatI claim as new, and desire to secure by Letters Patent, is

1. A mortising--.hisel made substantially square in cross-section and having an interior longitudinal chip-passage terminating at one end in an arch, the central ribs arranged on the inner opposing sides of the arch, and the lateral discharge-openings communicating with the chip-passage, substantially as 4described, for the purpose set forth.

2. A chisel for cutting mortises, formed of a single piece of metal and having an interior chip-passage, the cuttingedges, the inclined or arched sides provided with the centrally and longitudinally arranged ribs on their opposing faces, and the lateral discharge'openings, substantially as described, for the purpose set forth.

In testimony that I claim thc foregoing as my own I have hereto aiiixed my signature in presence of two witnesses.

JOHN El) DONALDSON.

Witnesses:

LEWIS R. YOUNG, WILLIAM HARRrNG'roN. 

